DE 199 61 617 A1, DE 199 51 966 A1 or DE 101 42 625 A1 have made known a neck rest which has a supporting member adapted to be advanced to the front on the head of the seat used, and a shock member which actuates it. When there is an impact onto the rear end of the vehicle the shock member is actuated and the supporting member is advanced to the front. The supporting member is mounted on the upholstering carrier via pivoting arms. In DE 199 51 966 A1, the supporting member forms part of the neck rest upholstering which is composed of two components which are interconnected via joints. The shock member can interact with the supporting member via a pulling cable and be in communication with a releasing element.
DE 102 08 620 describes a neck rest for automobile seats which has a fixed support portion as well as a second support portion for a movable upholstering portion which is movably supported by the first support portion. The second support portion is pivotally supported about a lower horizontal axis on the first support portion and an actuation device is formed by a spring which biases the second support portion. A controllable locking device retains the second support portion in the retracted position on the first support portion. A third support portion is slidably mounted on the second support portion between a lower and an upper position. The third support portion is biased to the upper position by means of a second spring. A controllable second locking device retains the third support portion in the lower position with second locking device being unlocked once the second support portion has reached a predetermined pivoting angle. Further, stop means are provided between the second and third support portions and the first support portion when the second and third support portions have arrived at their extracted positions, to prevent the latter from pivoting back. The structure described last is intended to achieve an optimum absorption of force with the sitting person not undergoing a risk of injury when there is a rear-end shock.